POLYPROPYLENE CABLE JACKET COMPOSITIONS WITH ENHANCED MELT STRENGTH AND PHYSICAL PROPERTIES

摘要

The present invention is a cable comprising one or more telecommunication orpower transmission media or a core of two or more such media, each medium orcore surrounded by at least one jacketing or sheathing layer comprising apolypropylene homopolymer or copolymer and having a relaxation spectrum (RSI)and melt flow (MF) such that RSI*MF¬a is greater than about 12 when a is about0.5. Significantly, the jacketing or sheathing layer exhibits advantagedextrusion fabrication characteristics, resulting from the propylene polymerhaving enhanced rheology properties (as demonstrated by its high relaxationspectrum index (RSI)). Additionally, the propylene-based polymer compositionof the present invention exhibits relatively high melt strength compared tocompounds of conventional propylene polymers or ethylene polymers. In fiberoptic cable jacketing applications, the present invention advantageouslybalances low post extrusion shrinkage with high modulus/deformation resistance.